| Message ID | 20200924180429.10016-1-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd() | expand |
Sean Christopherson <sean.j.christopherson@intel.com> writes: > Explicitly check that kvm_x86_ops.tlb_remote_flush() points at Hyper-V's > implementation for PV flushing instead of assuming that a non-NULL > implementation means running on Hyper-V. Wrap the related logic in > ifdeffery as hv_remote_flush_tlb() is defined iff CONFIG_HYPERV!=n. > > Short term, the explicit check makes it more obvious why a non-NULL > tlb_remote_flush() triggers EPTP shenanigans. Long term, this will > allow TDX to define its own implementation of tlb_remote_flush() without > running afoul of Hyper-V. > > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > arch/x86/kvm/vmx/vmx.c | 7 +++++-- > arch/x86/kvm/vmx/vmx.h | 2 ++ > 2 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 6f9a0c6d5dc5..a56fa9451b84 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -3073,14 +3073,15 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd, > eptp = construct_eptp(vcpu, pgd, pgd_level); > vmcs_write64(EPT_POINTER, eptp); > > - if (kvm_x86_ops.tlb_remote_flush) { > +#if IS_ENABLED(CONFIG_HYPERV) > + if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) { > spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock); > to_vmx(vcpu)->ept_pointer = eptp; > to_kvm_vmx(kvm)->ept_pointers_match > = EPT_POINTERS_CHECK; > spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock); > } > - > +#endif > if (!enable_unrestricted_guest && !is_paging(vcpu)) > guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr; > else if (test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) > @@ -6956,7 +6957,9 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) > > static int vmx_vm_init(struct kvm *kvm) > { > +#if IS_ENABLED(CONFIG_HYPERV) > spin_lock_init(&to_kvm_vmx(kvm)->ept_pointer_lock); > +#endif > > if (!ple_gap) > kvm->arch.pause_in_guest = true; > diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h > index d7ec66db5eb8..51107b7309bc 100644 > --- a/arch/x86/kvm/vmx/vmx.h > +++ b/arch/x86/kvm/vmx/vmx.h > @@ -316,8 +316,10 @@ struct kvm_vmx { > bool ept_identity_pagetable_done; > gpa_t ept_identity_map_addr; > > +#if IS_ENABLED(CONFIG_HYPERV) > enum ept_pointers_status ept_pointers_match; > spinlock_t ept_pointer_lock; > +#endif Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> In case ept_pointers_match/ept_pointer_lock are useless for TDX we may want to find better names for them to make it clear this is a Hyper-V thingy (e.g. something like hv_tlb_ept_match/hv_tlb_ept_lock). > }; > > bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
On Fri, Sep 25, 2020 at 11:59:00AM +0200, Vitaly Kuznetsov wrote: > Sean Christopherson <sean.j.christopherson@intel.com> writes: > > +#if IS_ENABLED(CONFIG_HYPERV) > > enum ept_pointers_status ept_pointers_match; > > spinlock_t ept_pointer_lock; > > +#endif > > Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> > > In case ept_pointers_match/ept_pointer_lock are useless for TDX we may > want to find better names for them to make it clear this is a Hyper-V > thingy (e.g. something like hv_tlb_ept_match/hv_tlb_ept_lock). Good call. I'll send a v2, looking at hv_remote_flush_tlb_with_range(), I think there are additional cleanups/optimizations that can be done, e.g. do the extra flushes only on vCPUs with a mistmatching EPTP instead of flushing all vCPUs' EPTPs if _any_ vCPU has a mismatched EPTP. > > > }; > > > > bool nested_vmx_allowed(struct kvm_vcpu *vcpu); > > -- > Vitaly >
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 6f9a0c6d5dc5..a56fa9451b84 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3073,14 +3073,15 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd, eptp = construct_eptp(vcpu, pgd, pgd_level); vmcs_write64(EPT_POINTER, eptp); - if (kvm_x86_ops.tlb_remote_flush) { +#if IS_ENABLED(CONFIG_HYPERV) + if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) { spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock); to_vmx(vcpu)->ept_pointer = eptp; to_kvm_vmx(kvm)->ept_pointers_match = EPT_POINTERS_CHECK; spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock); } - +#endif if (!enable_unrestricted_guest && !is_paging(vcpu)) guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr; else if (test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail)) @@ -6956,7 +6957,9 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) static int vmx_vm_init(struct kvm *kvm) { +#if IS_ENABLED(CONFIG_HYPERV) spin_lock_init(&to_kvm_vmx(kvm)->ept_pointer_lock); +#endif if (!ple_gap) kvm->arch.pause_in_guest = true; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index d7ec66db5eb8..51107b7309bc 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -316,8 +316,10 @@ struct kvm_vmx { bool ept_identity_pagetable_done; gpa_t ept_identity_map_addr; +#if IS_ENABLED(CONFIG_HYPERV) enum ept_pointers_status ept_pointers_match; spinlock_t ept_pointer_lock; +#endif }; bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
Explicitly check that kvm_x86_ops.tlb_remote_flush() points at Hyper-V's implementation for PV flushing instead of assuming that a non-NULL implementation means running on Hyper-V. Wrap the related logic in ifdeffery as hv_remote_flush_tlb() is defined iff CONFIG_HYPERV!=n. Short term, the explicit check makes it more obvious why a non-NULL tlb_remote_flush() triggers EPTP shenanigans. Long term, this will allow TDX to define its own implementation of tlb_remote_flush() without running afoul of Hyper-V. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/vmx/vmx.c | 7 +++++-- arch/x86/kvm/vmx/vmx.h | 2 ++ 2 files changed, 7 insertions(+), 2 deletions(-)